From 297dca28f3dd1f3ded97c7539823900294efb4da Mon Sep 17 00:00:00 2001
From: Hatter Jiang <jht5945@gmail.com>
Date: Sat, 7 Nov 2020 21:41:04 +0800
Subject: [PATCH] feat: add args

---
 __enclave/virt_enclave/examples/sign_file.rs | 13 ++++++++++++-
 1 file changed, 12 insertions(+), 1 deletion(-)

diff --git a/__enclave/virt_enclave/examples/sign_file.rs b/__enclave/virt_enclave/examples/sign_file.rs
index 0dc4fa2..ff0a06d 100644
--- a/__enclave/virt_enclave/examples/sign_file.rs
+++ b/__enclave/virt_enclave/examples/sign_file.rs
@@ -1,4 +1,4 @@
-use std::io::Read;
+use std::io::{ Read, Write };
 use std::fs::File;
 use ring::digest;
 use virt_enclave::sig::*;
@@ -31,4 +31,15 @@ fn main() {
     println!("File  : {}", f);
     println!("Hex   : {}", digest_hex);
     println!("Signed: {}", serde_json::to_string(&signed_message).unwrap());
+
+    if let Some(of) = args.next() {
+        if File::open(&of).is_ok() {
+            println!("Output file exists: {}", of);
+            return;
+        }
+        if let Ok(mut out_file) = File::create(&of) {
+            out_file.write_all(&serde_json::to_string(&signed_message).unwrap().as_bytes()).ok();
+            println!("Write file successed: {}", of);
+        }
+    }
 }
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